One of the most common services that locksmiths provide is cutting keys to fit locks. Some typical examples of many reasons for cutting keys are to replace a lost or broken key, to provide additional keys for new users of an existing lock and to provide new keys to keyholders of an existing lock that is changed for security reasons.
Very broadly described, keys are commonly cut from male blanks that have blade dimensions and profile shapes that are designed to mate with the female slot-shaped keyways of a particular manufacturer's brand and model locks. That is, a blank for a selected manufacturer's brand and model will slide into the keyways of all such brand/model locks.
For keys with an asymmetrical blade profile (sometimes referred to herein as the “side view profile” of a blade), frequently multiple cuts at uniformly separated positions along the length are made to depths of specified distances. Customarily cut depths are specified by the height of the blade remaining after a cut from the blade bottom. The longitudinal spacing between adjacent cuts and the shape of the cuts, i.e., width of cut, whether V-shaped, straight-bottomed, rounded bottomed, etc., is selected to match the space between and shape of the pins for the brand and model of lock. The specific sequence of depths of cut at respective positions along the length of the blade defines a side view profile seen as peaks and valleys. When a key is inserted into a matching brand/model lock, springs force the pins at each space position to the depth of the corresponding valley. The plug of the lock will only revolve to actuate the lock if each and every one of the pins is exactly as long as the distance between the valley and the shear line of the plug. In principle, a specific lock of a brand and model has its own unique combination of pin lengths and space positions. Consequently, only a key which allows all the pins to exactly fill the shear line-to-valley distances will operate that specific lock.
By industry convention, the positions of the cut spaces are identified in numerical sequence from key bow to tip starting with position “1”. There can be any number of cut positions, however, in practice most commercially offered modern locks and keys in everyday use have about five or six set apart by a uniform center-to-center spacing. The Sargent® lock brand, with which this invention is primarily concerned, utilizes up to seven positions. Also, the depth of cut is identified in whole number units which for the Sargent brand range in designation from 1 to 10 in which “1” corresponds to no depth, i.e., the blank is not cut, and in which “10” corresponds to maximum depth. The term “depth of cut” as used herein means the distance from the top of the blade of blade material removed by the cut and is different from the customary cut depth measurement, mentioned above, that is typically used in the industry. The incremental depth of cuts is normally uniform for a given model and brand of lock. Thus a numerical sequence such as “5, 2, 6, 3, 4, 4” for example specifies a key cut configuration in which the first position is five increments deep, the second position is two increments deep, the third position is six increments deep, and so forth. Moreover, only a blank with a blade shape fitting into a manufacturer's brand “X” and model “Y” lock which is cut to a 5, 2, 6, 3, 4, 4 configuration in accordance with that brand and model spacing and depth increments will actuate the brand “X”, model “Y” lock equipped with a sequence of 5, 2, 6, 3, 4, 4, 1 pins. The numerical sequence of cut depths is the key code (known in the locksmith industry as the “bitting” code for the key) of that specific lock.
The side view profile of a key code can be machined into a blank in various conventional ways. Two very common methods are cutting and punch pressing. In the former, a cutting wheel rotates against and edge of the blank. As the cutting wheel advances along the length of the blade, the wheel is moved toward and away from the blank at each cut position thereby cutting away blank material to desired depth of cut. In punch-pressing, the edge of the blank at a preselected longitudinal position is placed in the nip between appropriately shaped die and punch tool components. The punch plunges through the blank to stamp out a void corresponding to the desired depth of cut.
Non-duplicating machines for cutting key blanks, i.e., machines which do not simultaneously copy the side view profile of an existing key, are usually complex, bulky, heavy, electrically power driven. They are thus not easily transportable from site to site where a locksmith is frequently called upon to cut keys. The cutting wheels of these machines wear down with use and must be renewed and adjusted relatively frequently to maintain quality performance. Also, such machines normally can be variably controlled to operate within key cutting parameter ranges such as position spacing, depth of cut increments, widths of cut, etc. This enables one machine to cut keys of different lock manufacturers and models. Because such machines are equipped to provide broad operational flexibility, they are relatively expensive. Furthermore, as will be explained in greater detail below, a certain popular manufacturer's keys have side view profiles that even expensive electrically power driven key cutters operated by reasonably skilled technicians cannot consistently produce to code.
Manual punch presses are relatively small, light weight and portable. An example of a well known, high quality punch press key cutter is Pro-lok® “Blue Punch” key machine No. BP201 (Pro-Lok Corporation, Orange, Calif.). The Pro-lok Blue Punch machine is particularly useful because once properly adjusted, the spacing positions and the depths of cut are controlled with precision by mechanical components. As a result the effect of operator skill on achieving consistently successful key cuts is reduced.
As mentioned, the blade of the key is milled along its length to have an end view profile that uniquely mates with the female keyway of a particular brand and model of lock. By the term “end view profile” is meant the axial direction cross section shape as seen in section view FIG. 2 of the blade 1 of key blank 10 (FIG. 1). A manufacturer may choose any end view profile. Typically keys have a flat blade surface parallel to the plane of the blade on one or both sides of their end view profile near the bottom edge of the blade (region “A”, FIG. 2). This facilitates clamping the blade in a holder so that a blank can be cut with a lock code. Usually keys also have irregular blade surfaces profiles near the top edge of the blade (region “B”). Stock Pro-lok Blue Punch key machines are designed to grip the blade between clamping jaws such that the flat sides of the blank blade lies flush against the opposing jaws. The plane of the blade is thus maintained perpendicular to the punch direction causing punch action to produce a cut of depth that is uniform across the full width of the blade.
Stock Pro-lok Blue Punch key machines also are factory pre-set to automatically advance the carriage holding the punch and die exactly one space position when a cut is punched. As a result, the punch is laterally aligned along the blade length to carry out the next sequential cut as soon as the operator resets the code bar to adjust fore-aft location of the jaws for proper depth of the next cut. However, stock machines are limited in that the jaw carriage of any particular machine automatically advances in only one direction, i.e., either left-to-right or right-to-left.
The ability to grip the flat surfaces of the blanks near the bottom edge and the one-direction carriage advance, among other conditions and parameters, generate a primary drawback of the Blue Punch key machine. It is that a separate machine must be used for selected lock brands and models/key series within brands. For example there are separate Blue Punch key machine models for Corbin®, Schlage®, Kwikset®, Weslock® and other brands. More specifically, the Blue Punch model BP201C70 can cut Corbin system 70, series 59 type A1, A2, B1, B2, D2, and 6 pin series 60 keys. A different Blue Punch machine is needed to cut certain Schlage keys. Because each Blue Punch machine only cuts keys for a limited selection of locks, locksmiths need to procure a large number of machines to be able to cut a wide variety of keys. Nonetheless, there has been acceptance of this machine in the market. However, it is desirable to have a punch machine capable of cutting as many different series of keys as possible.
Another drawback of all known conventional punch press machines and one from which the Blue Punch key machine also suffers prior to this invention is the inability to cut Sargent® brand keys. Sargent locks have pins with a 51 mil (0.051 inch) wide flat bottom and a 78-79° bottom angle. The depth of cut increment for a Sargent key is 20 mils (0.020 inch) and the inter-position spacing is 156 mils (0.156 inch). Cumulatively, these specifications impose a prohibitively small maximum adjacent cuts (“MACS”) limitation on the key cutting machine of seven. That is, it is normally not possible to have a difference of cut depths of eight units or more (8×20 mils=160 mils) between successive cut positions. When stamping out a greater adjacent cut difference of 8 or 9 units, the punch width extends laterally beyond the position spacing of the deeper cut and removes key material of the adjacent shallower cut. In effect, that shallow cut becomes deeper than called for by the code and therefore the pin at that position will prevent the plug from turning. Sargent keys having codes which contain the sequences “1,9”, “9,1”, “1,10”, “10,1”, “2,10” and “10,2” cannot routinely and consistently be cut by any punch presses or electric code machines.
Although traditional cutting machines may be able to cut to code Sargent brand keys with MACS values of seven, in commercial practice even highly trained and skilled technicians using advanced electrically driven cutting machines typically experience poor consistency and quality. Consequently, other than by purchasing replacement keys from the original equipment supplier, and now by using this invention, there is no known device for or method of reliably obtaining Sargent keys cut to code. Sargent keys with MACS as high as seven are in service and there is a need for locksmiths to cut such key codes.
It is desirable to have a manual and portable punch press machine that is capable of consistently cutting Sargent keys to code. Notwithstanding the difficulties presented by the geometry of Sargent brand keys and locks, it is now been discovered that certain modifications to the Pro-lok Blue Punch key machine can enable the cutting of common Sargent keys with a MACS as high as seven. Thus in one aspect, this invention relates to a manual punch press for cutting selected Sargent keys to all commercially encountered codes.
Two of the most popular of Sargent brand lock styles are the “L” and “R” series. Curiously they utilize blade end view profiles that are mirror images of each other. Given the limitations that flat sides of the blade are clamped by parallel facing jaws, and that the punch and die assembly advances laterally in only one direction, it would not be expected to cut both L and R series Sargent keys in a single Pro-lok Blue Punch key machine. To increase locksmithing productivity it is highly desirable to have ability to cut Sargent series L and R keys to code on a single punch press machine.